Transmission case vent

ABSTRACT

The present invention provides a transmission case assembly adapted for use with a motorcycle. The transmission case assembly includes a transmission case having a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber. The breather chamber is adapted to separate the lubricant-laden mist into lubricant and vapor and drain the separated lubricant into the gear chamber. The transmission case assembly also includes a transmission case cover coupled to the transmission case. The transmission case cover includes at least a portion of a passageway in fluid communication between the breather chamber and ambient air outside of the transmission case assembly. The passageway is adapted to exhaust the separated vapor outside of the transmission case assembly.

FIELD OF THE INVENTION

This invention relates generally to motorcycles, and more particularly to motorcycle transmissions.

BACKGROUND OF THE INVENTION

Motorcycle transmissions typically include vented transmission cases for exhausting pressurized vapor built-up in the transmission cases to the atmosphere. Such a vented transmission case typically includes a hose fitting coupled to an upper portion of the transmission, such as on a transmission case top cover. An inverted U-shaped hose is typically coupled to the hose fitting to allow the pressurized vapor to exit the transmission case, while causing lubricant entrained in the pressurized vapor to condense and drain back to the transmission case.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, a transmission case assembly adapted for use with a motorcycle. The transmission case assembly includes a transmission case having a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber. The breather chamber is adapted to separate the lubricant-laden mist into lubricant and vapor and drain the separated lubricant into the gear chamber. The transmission case assembly also includes a transmission case cover coupled to the transmission case. The transmission case cover includes at least a portion of a passageway in fluid communication between the breather chamber and ambient air outside of the transmission case assembly. The passageway is adapted to exhaust the separated vapor outside of the transmission case assembly.

The present invention provides, in another aspect, a transmission case assembly adapted for use with a motorcycle. The transmission case assembly includes a transmission case having a first interface portion, a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber to receive the lubricant-laden mist. The breather chamber is adapted to at least partially facilitate separation of the lubricant-laden mist into lubricant and vapor. The transmission case assembly also includes a transmission case cover including a second interface portion coupled to the first interface portion. The transmission case cover includes a vapor chamber in fluid communication with the breather chamber and adapted to receive the separated vapor. The transmission case assembly further includes a tortuous passageway fluidly communicating the gear chamber and ambient air outside of the transmission case assembly, at least a portion of the tortuous passageway passing through the first and second interface portions.

The present invention provides, in yet another aspect, a motorcycle including a front wheel, a rear wheel, a frame supported by the front and rear wheels, and a transmission case including a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber. The breather chamber is adapted to separate the lubricant-laden mist into lubricant and vapor and drain the separated lubricant into the gear chamber. The motorcycle also includes a transmission case cover coupled to the transmission case. The transmission case cover includes at least a portion of a passageway in fluid communication between the breather chamber and ambient air outside of the transmission case assembly. The passageway is adapted to exhaust the separated vapor outside of the transmission case assembly.

The present invention provides, in another aspect, a motorcycle including a front wheel, a rear wheel, a frame supported by the front and rear wheels, and a transmission case having a first interface portion, a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber to receive the lubricant-laden mist. The breather chamber is adapted to at least partially facilitate separation of the lubricant-laden mist into lubricant and vapor. The motorcycle also includes a transmission case cover including a second interface portion coupled to the first interface portion. The transmission case cover includes a vapor chamber in fluid communication with the breather chamber and adapted to receive the separated vapor. The motorcycle further includes a tortuous passageway fluidly communicating the gear chamber and ambient air outside of the transmission case, at least a portion of the tortuous passageway passing through the first and second interface portions.

The present invention provides, in yet another aspect, a transmission case cover adapted for use with a transmission case of a motorcycle. The transmission case includes a first interface portion and a breather chamber that receives a lubricant-laden mist during operation of the motorcycle. The breather chamber is adapted to at least partially facilitate separation of the lubricant-laden mist into lubricant and vapor. The transmission case cover includes a second interface portion adapted to couple to the first interface portion of the transmission case, a vapor chamber adapted to fluidly communicate with the breather chamber and adapted to receive the separated vapor, and a groove formed in the second interface portion to fluidly communicate the vapor chamber and ambient air outside of the transmission case, the groove adapted to exhaust the separated vapor outside of the transmission case.

Other features and aspects of the present invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like reference numerals indicate like parts:

FIG. 1 is a front perspective view of a motorcycle embodying the present invention.

FIG. 2 is an exploded, top perspective view of a transmission case assembly of the motorcycle of FIG. 1, illustrating a transmission case cover and a baffle.

FIG. 3 is a reverse perspective view of the transmission case cover of FIG. 2, illustrating a portion of a passageway or a groove formed in the transmission case cover.

FIG. 4 is an assembled, top view of the transmission case assembly of FIG. 2.

FIG. 5 is a cross-section view taken along line 5-5 of FIG. 4, illustrating a gear chamber, breather chamber, and vapor chamber.

FIG. 6 is a perspective, cross-section view taken along line 6-6 of FIG. 4, illustrating a lubricant-laden mist entering the breather chamber and separated vapor entering the vapor chamber.

FIG. 7 is a perspective, cross-section view taken along line 7-7 of FIG. 4, illustrating the separated vapor passing through the vapor chamber.

FIG. 8 is a perspective, partial cross-section view taken along line 8-8 of FIG. 4, illustrating separated vapor exiting the transmission case assembly via the groove formed in the transmission case cover.

FIG. 9 is an assembled, top perspective view of the transmission case assembly of FIG. 2, illustrating a passageway between the transmission case cover and the transmission case through which the separated vapor can exit.

Before any features of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including”, “having”, and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of letters to identify elements of a method or process is simply for identification and is not meant to indicate that the elements should be performed in a particular order.

DETAILED DESCRIPTION

FIG. 1 illustrates a motorcycle 10 including a drive assembly 14, a frame 18, a front fork assembly 22, a swing arm or rear fork assembly 26, a front wheel 30, a rear wheel 34, a seat 38, and a fuel tank 42. The frame 18 supports the drive assembly 14, the front fork assembly 22, the rear fork assembly 26, the seat 38, and the fuel tank 42. The front fork assembly 22 is pivotally supported at a front end of the motorcycle 10 and supports the front wheel 30. The front fork assembly 22 includes a pair of handle bars 46 for steering the motorcycle 10. The rear fork assembly 26 is coupled to the frame 18 at a rear end of the motorcycle 10 and rotatably supports the rear wheel 34. The seat 38 is coupled to the frame 18 and is configured for supporting a rider. The fuel tank 42 is supported by the frame 18 and provides fuel to the drive assembly 14.

The drive assembly 14 is preferably coupled to the frame 18 beneath the seat 38 between the front wheel 30 and the rear wheel 34 of the motorcycle 10. With continued reference to FIG. 1, the drive assembly 14 includes an engine 50 and a transmission 54. The engine 50 and the transmission 54 comprise distinct, independent components of the drive assembly 14. The engine 50 preferably comprises a V-twin engine 50 supported by the frame 18 forward of the transmission 54. The engine 50 includes an output shaft (not shown), such as a crankshaft, which includes a primary drive sprocket (not shown) for driving a primary chain (not shown) in a conventional manner to power the transmission 54.

With reference to FIG. 2, the transmission 54 includes a transmission case assembly 58 including a transmission case 62 enclosing the internal components (not shown) of the transmission 54. A gear chamber 66 in the transmission case (see FIG. 5) houses the internal components of the transmission 54, particularly the transmission input and output shafts and various gears (not shown). Transmission lubricant is contained within the gear chamber 66 to lubricate the working components of the transmission (e.g., the input and output shafts and various gears). The transmission case assembly 58 also includes a pan 70 coupled to the transmission case 62. The pan 70 includes a reservoir or sump 74 for containing engine lubricant, which is distributed throughout the engine 50 to lubricate the working components of the engine 50. The engine lubricant is kept separately from the transmission lubricant, such that there is no cross-contamination between the engine lubricant and transmission lubricant.

The transmission case 62 also includes a breather chamber 78 in fluid communication with the gear chamber 66. With reference to FIG. 6, an inlet aperture 82 fluidly communicates the gear chamber 66 and the breather chamber 78, such that lubricant-laden mist in the gear chamber 66 may enter the breather chamber 78 via the inlet aperture 82. An outlet aperture 86 fluidly communicating the breather chamber 78 and the gear chamber 66 allows separated lubricant to drain back to the gear chamber 66.

With reference to FIG. 2, the transmission case assembly 58 also includes a transmission case cover 90 coupled to the transmission case 62 and a gasket 94 positioned between the transmission case cover 90 and the transmission case 62. Multiple fasteners, such as bolts 98 (see FIG. 9), may be used to secure the transmission case cover 90 and gasket 94 to the transmission case 62. With reference to FIGS. 3, 6, and 7, the transmission case cover 90 includes a partition or rib 102 that, when the transmission case cover 90 is coupled to the transmission case 62, abuts an upper surface 104 of a side wall 106 of the breather chamber 78 to substantially isolate the breather chamber 78 and the gear chamber 66. Due to the seal created by the rib 102, gasket 94, and side wall 106 of the breather chamber 78, the inlet aperture 82 and outlet aperture 86 are the only paths to fluidly communicate the breather chamber 78 and gear chamber 66.

With reference to FIGS. 2, 6, and 7, the gasket 94 includes a baffle 110 having a plurality of holes or apertures 114 therethrough. When the gasket 94 is coupled between the transmission case cover 90 and the transmission case 62, the baffle 110 acts as an upper wall of the breather chamber 78, and a lower wall of a vapor chamber 118 formed in the transmission case cover 90 (see FIG. 5). As shown in FIGS. 6 and 7, the apertures 114 in the baffle 110 provide the only paths to fluidly communicate the breather chamber 78 and the vapor chamber 118. Generally, the baffle 110 facilitates the separation of lubricant from the lubricant-laden mist in the breather chamber 78 and allows the separated vapor to enter the vapor chamber 118 via the apertures 114. In the illustrated construction, three apertures 114 are formed in the baffle 110. Alternatively, more or less than three apertures 114 may be formed in the baffle 110 to fluidly communicate the breather chamber 78 and the vapor chamber 118. Also, in the illustrated construction, the apertures 114 are formed in a corner of the baffle 110 on a side of the transmission 54 away from the apertures 82, 86. Alternatively, the apertures 114 may be formed in the middle of the baffle 110, or along a side edge of the baffle 110.

With reference to FIG. 3, the transmission case cover 90 includes a portion of a passageway or a groove 122 formed in an interface portion 126 of the transmission case cover 90. In the illustrated construction, the groove 122 is positioned adjacent the rib 102 on a side of the transmission case cover 90 that corresponds with the vapor chamber 118. As such, the groove 122 is positioned on a side of the transmission case cover 90 opposite from where the apertures 114 are disposed in the baffle 110. Alternatively, the apertures 114 and groove 122 may be positioned on adjacent sides of the vapor chamber 118. Also, in the illustrated construction, the groove 122 terminates before reaching the outer peripheral edge of the interface portion 126.

With reference to FIG. 2, the transmission case 62 includes an ear 130 extending from an interface portion 134. The ear 130 defines an upper surface 138 substantially coplanar with the interface portion 134 of the transmission case 62. The ear 130 is substantially L-shaped, such that the ear 130 forms a groove 142 in the transmission case 62 between the upper surface 138 of the ear 130 and the interface portion 134 of the transmission case 62. As shown in FIG. 2, the groove 142 opens to or transitions to the exterior surface of the transmission case 62. The gasket 94 also includes an ear 146 having substantially the same shape as the ear 130 on the transmission case 62, such that the ear 146 on the gasket 94 is configured to lie over the ear 130 of the transmission case 62.

With reference to FIG. 8, when the transmission case cover 90 is coupled to the transmission case 62, the groove 122 provides a passageway 150 between the respective interface portions 126, 134 of the transmission case cover 90 and the transmission case 62. The passageway 150 fluidly communicates the vapor chamber 118 and ambient air outside of the transmission case 62. In the illustrated construction, the passageway 150 is integrally formed with the transmission case cover 90 and the transmission case 62, such that the transmission case cover 90 and the transmission case 62 may be cast with the grooves 122, 142.

During operation of the motorcycle 10, the internal working components of the transmission 54 (e.g., the shafts and gears) generate lubricant-laden mist in the gear chamber 66. In addition, as the transmission lubricant is heated, air or vapor in the gear chamber 66 may also be heated and expand. As the air or vapor in the gear chamber 66 expands, lubricant-laden mist may be carried from the gear chamber 66 to the breather chamber 78. As shown in FIG. 6, a solid arrow 154 represents lubricant-laden mist entering the breather chamber 78 through the inlet aperture 82. Once in the breather chamber 78, the temperature of the lubricant-laden mist is reduced, thereby causing at least a portion of the lubricant entrained in the lubricant-laden mist to separate or drop out. In addition, swirling or turbulent motion of the lubricant-laden mist may cause at least a portion of the lubricant entrained in the lubricant-laden mist to separate or drop out. The separated lubricant accumulates in the bottom of the breather chamber 78 and subsequently drains back to the sump 74 via the outlet aperture 86 (indicated by dashed arrow 158). In the illustrated construction, no additional structure is utilized in the breather chamber 78 to reduce the speed of the lubricant-laden mist or facilitate or enhance the turbulent motion of the lubricant-laden mist. Alternatively, additional structure may be positioned in the breather chamber 78 to reduce the speed of the lubricant-laden mist or enhance the swirling or turbulent motion of the lubricant-laden mist in the breather chamber 78.

The baffle 110 may also cause at least a portion of the lubricant entrained in the lubricant-laden mist to separate or drop out. Particularly, the restriction provided by the apertures 114 in the baffle 110 may reduce the speed of the lubricant-laden mist, causing at least a portion of the lubricant entrained in the lubricant-laden mist to separate or drop out. The separated vapor (indicated by dashed arrow 162), therefore, may then enter the vapor chamber 118 through the apertures 114 in the baffle 110.

With reference to FIG. 7, solid arrows 166 illustrate separated vapor moving upwardly through the apertures 114 in the baffle 110 and transversely through the vapor chamber 118 toward the passageway 150. With reference to FIG. 8, solid arrows 170 illustrate the separated vapor exhausting through the passageway 150 to a location outside of the transmission case assembly 58. In other words, the separated vapor passes through the respective interface portions 126,134 of the transmission case cover 90 and the transmission case 62 to exhaust to a location outside of the transmission case assembly 58.

Specifically, with continued reference to FIG. 8, the separated vapor first passes through the portion of the passageway 150 defined by the groove 122 between the interface portion 126 of the transmission case cover 90 and the interface portion 134 of the transmission case 62. The separated vapor then passes through the portion of the passageway 150 defined by the groove 142 between the ear 130 and the interface portion 134 of the transmission case 62. Finally, as the groove 142 opens to the exterior surface of the transmission case 62, the separated vapor may disperse and mix with the ambient air outside of the transmission case assembly 58.

With reference to FIGS. 6-9, the gear chamber 66, the inlet aperture 82, the breather chamber 78, the apertures 114 in the baffle 110, the vapor chamber 118, the portion of the passageway 150 defined by the groove 122 between the interface portion 126 of the transmission case cover 90 and the interface portion 134 of the transmission case 62, and the portion of the passageway 150 defined by the groove 142 between the ear 130 and the interface portion 134 of the transmission case 62 may combine to yield a tortuous passageway through which lubricant-laden mist and/or separated vapor must pass before the separated vapor is exhausted outside of the transmission case assembly 58. Such a tortuous passageway may reduce the amount lubricant-laden mist that escapes from the transmission case assembly 58. Such a tortuous passageway may also substantially prevent foreign liquids (e.g., water) from entering the transmission case assembly 58.

Various aspects of the invention are set forth in the following claims. 

1. A transmission case assembly adapted for use with a motorcycle, the transmission case assembly comprising: a transmission case including a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber, the breather chamber adapted to separate the lubricant-laden mist into lubricant and vapor and drain the separated lubricant into the gear chamber; and a transmission case cover coupled to the transmission case, the transmission case cover including at least a portion of a passageway in fluid communication between the breather chamber and ambient air outside of the transmission case assembly, the passageway adapted to exhaust the separated vapor outside of the transmission case assembly.
 2. The transmission case assembly of claim 1, further comprising: a vapor chamber in the transmission case cover, wherein the passageway is in fluid communication between the vapor chamber and ambient air outside of the transmission case assembly; and a baffle positioned between the breather chamber and the vapor chamber, wherein the baffle at least partially restricts fluid flow between the breather chamber and the vapor chamber, and wherein the baffle is adapted to facilitate separation of the lubricant-laden mist into lubricant and vapor.
 3. The transmission case assembly of claim 2, wherein the baffle comprises a gasket including at least one aperture to fluidly communicate the breather chamber and the vapor chamber.
 4. The transmission case assembly of claim 3, wherein the at least one aperture is positioned on a side of the gasket opposite the portion of the passageway in the transmission case cover.
 5. The transmission case assembly of claim 1, wherein the transmission case includes a first interface portion, wherein the transmission case cover includes a second interface portion coupled to the first interface portion, and wherein the passageway passes through the first interface portion and the second interface portion.
 6. The transmission case assembly of claim 5, further comprising an ear extending from the first interface portion, wherein the ear at least partially defines a groove in the transmission case, and wherein the groove comprises a portion of the passageway.
 7. The transmission case assembly of claim 1, wherein the transmission case cover includes a groove comprising the portion of the passageway.
 8. The transmission case assembly of claim 1, wherein the passageway is integrally formed with the transmission case cover and the transmission case.
 9. A transmission case assembly adapted for use with a motorcycle, the transmission case assembly comprising: a transmission case including a first interface portion, a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber to receive the lubricant-laden mist, the breather chamber adapted to at least partially facilitate separation of the lubricant-laden mist into lubricant and vapor; a transmission case cover including a second interface portion coupled to the first interface portion, the transmission case cover including a vapor chamber in fluid communication with the breather chamber and adapted to receive the separated vapor; and a tortuous passageway fluidly communicating the gear chamber and ambient air outside of the transmission case assembly, at least a portion of the tortuous passageway passing through the first and second interface portions.
 10. The transmission case assembly of claim 9, further comprising a baffle positioned between the breather chamber and the vapor chamber, the baffle at least partially restricting fluid flow between the breather chamber and the vapor chamber, the baffle adapted to facilitate separation of the lubricant-laden mist into lubricant and vapor, the breather chamber adapted to accumulate the separated lubricant and drain the separated lubricant into the gear chamber, wherein at least a portion of the tortuous passageway passes through the baffle.
 11. The transmission case assembly of claim 10, wherein the baffle comprises a gasket including at least one aperture to fluidly communicate the breather chamber and the vapor chamber.
 12. The transmission case assembly of claim 11, wherein the at least one aperture is positioned on a side of the gasket opposite the portion of the tortuous passageway passing through the first and second interface portions.
 13. The transmission case assembly of claim 9, further comprising an ear extending from the first interface portion, wherein the ear at least partially defines a groove in the transmission case, and wherein the groove comprises a portion of the tortuous passageway.
 14. The transmission case assembly of claim 9, wherein the second interface portion includes a groove, and wherein the groove comprises a portion of the tortuous passageway.
 15. The transmission case assembly of claim 9, wherein at least a portion of the tortuous passageway is integrally formed with the transmission case cover and the transmission case.
 16. A motorcycle comprising: a front wheel; a rear wheel; a frame supported by the front and rear wheels; a transmission case including a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber, the breather chamber adapted to separate the lubricant-laden mist into lubricant and vapor and drain the separated lubricant into the gear chamber; and a transmission case cover coupled to the transmission case, the transmission case cover including at least a portion of a passageway in fluid communication between the breather chamber and ambient air outside of the transmission case assembly, the passageway adapted to exhaust the separated vapor outside of the transmission case assembly.
 17. The transmission case assembly of claim 16, further comprising: a vapor chamber in the transmission case cover, wherein the passageway is in fluid communication between the vapor chamber and ambient air outside of the transmission case assembly; and a baffle positioned between the breather chamber and the vapor chamber, wherein the baffle at least partially restricts fluid flow between the breather chamber and the vapor chamber, and wherein the baffle is adapted to facilitate separation of the lubricant-laden mist into lubricant and vapor.
 18. The motorcycle of claim 17, wherein the baffle comprises a gasket including at least one aperture to fluidly communicate the breather chamber and the vapor chamber.
 19. The motorcycle of claim 18, wherein the at least one aperture is positioned on a side of the gasket opposite the portion of the passageway in the transmission case cover.
 20. The motorcycle of claim 16, wherein the transmission case includes a first interface portion, wherein the transmission case cover includes a second interface portion engaged with the first interface portion, and wherein the passageway passes through the first interface portion and the second interface portion.
 21. The motorcycle of claim 20, further comprising an ear extending from the first interface portion, wherein the ear at least partially defines a groove in the transmission case, and wherein the groove comprises a portion of the passageway.
 22. The motorcycle of claim 16, wherein the transmission case cover includes a groove comprising the portion of the passageway.
 23. The motorcycle of claim 16, wherein the passageway is integrally formed with the transmission case cover and the transmission case.
 24. A motorcycle comprising: a front wheel; a rear wheel; a frame supported by the front and rear wheels; a transmission case including a first interface portion, a gear chamber adapted to contain a lubricant and generate a lubricant-laden mist during operation of the motorcycle, and a breather chamber in fluid communication with the gear chamber to receive the lubricant-laden mist, the breather chamber adapted to at least partially facilitate separation of the lubricant-laden mist into lubricant and vapor; a transmission case cover including a second interface portion coupled to the first interface portion, the transmission case cover including a vapor chamber in fluid communication with the breather chamber and adapted to receive the separated vapor; and a tortuous passageway fluidly communicating the gear chamber and ambient air outside of the transmission case, at least a portion of the tortuous passageway passing through the first and second interface portions.
 25. The motorcycle of claim 24, further comprising a baffle positioned between the breather chamber and the vapor chamber, the baffle at least partially restricting fluid flow between the breather chamber and the vapor chamber, the baffle adapted to facilitate separation of the lubricant-laden mist into lubricant and vapor, the breather chamber adapted to accumulate the separated lubricant and drain the separated lubricant into the gear chamber, wherein at least a portion of the tortuous passageway passes through the baffle.
 26. The motorcycle of claim 25, wherein the baffle comprises a gasket including at least one aperture to fluidly communicate the breather chamber and the vapor chamber.
 27. The motorcycle of claim 26, wherein the at least one aperture is positioned on a side of the gasket opposite the portion of the tortuous passageway passing through the first and second interface portions.
 28. The motorcycle of claim 24, further comprising an ear extending from the first interface portion, wherein the ear at least partially defines a groove in the transmission case, and wherein the groove comprises a portion of the tortuous passageway.
 29. The motorcycle of claim 24, wherein the second interface portion includes a groove, and wherein the groove comprises a portion of the tortuous passageway.
 30. The motorcycle of claim 24, wherein at least a portion of the tortuous passageway is integrally formed with the transmission case cover and the transmission case.
 31. A transmission case cover adapted for use with a transmission case of a motorcycle, the transmission case including a first interface portion and a breather chamber that receives a lubricant-laden mist during operation of the motorcycle, the breather chamber adapted to at least partially facilitate separation of the lubricant-laden mist into lubricant and vapor, the transmission case cover comprising: a second interface portion adapted to couple to the first interface portion of the transmission case; a vapor chamber adapted to fluidly communicate with the breather chamber and adapted to receive the separated vapor; and a groove formed in the second interface portion to fluidly communicate the vapor chamber and ambient air outside of the transmission case, the groove adapted to exhaust the separated vapor outside of the transmission case.
 32. The transmission case cover of claim 31, wherein the groove is integrally formed with the transmission case cover. 